"William Klein + Daido Moriyama is the first exhibition to examine the relationship between the work of William Klein, one of the 20th century's most important photographers and film-makers, and that of Daido Moriyama, the most celebrated photographer to emerge from the Japanese Provoke movement," says the Tate. "Taking as its central theme the cities of New York and Tokyo, William Klein + Daido Moriyama explores both artists' celebrated depictions of modern urban life."

The exhibition, which opened yesterday, will run until 20 January 2013. BJP has partnered with Tate Modern to offer two tickets for the price of one to all BJP iPhone app users, representing a saving of £12.70. 

The offer coincides with the release of a new issue of BJP's iPhone app dedicated to Daido Moriyama's work. The iPhone app and related Moriyama issue are free to download.

The offer is available on full-price tickets for William Klein + Daido Moriyama at Tate Modern, from 10 October until 20 January 2013. It is available on presentation of a valid British Journal of Photography iPhone app digital voucher, at Tate Modern ticket desks only.

The William Klein + Daido Moriyama exhibition is open every day from 10am to 6pm, and until 10pm on Fridays and Saturdays. For more details about the exhibition, visit the Tate website. To download BJP's iPhone app, visit the App Store.